A majority of cellular phones and devices available today have both voice call and data capabilities. Smart phones can be used to browse the internet, retrieve e-mail, and download streaming content, among other things. In order to receive voice calls or text messages on conventional cellular systems, however, cell phones must be connected to the cellular network. In this manner, a page can be sent through the system to a user's cell phone alerting the user of an incoming call or text message, for example. If the user does not answer, the call may be rerouted to voicemail, for example, or the text message held in queue until the user reconnects.
In some cases, the user may not receive a page because the user's phone is off, their battery is dead, or they are out of network range. In other cases, the user may turn off cellular service because they are connected to an inter-working wireless local area network (I-WLAN), for example. Even with advanced cellular technologies (e.g., 4G LTE), data can often be more efficiently transmitted over I-WLAN and other systems. In addition, disabling cellular service can also increase battery life because transmitting over shorter distances to an I-WLAN requires less power, among other things. With current technology, however, certain features, such as receiving cellular calls and sending and receiving some types of instant messaging (e.g., short messaging service (SMS) or multimedia messaging service (MMS) messages), for example, may not available, or may only be available at extra cost, when cellular services are disabled.